State of the art commercial vehicles are generally configured with rear drive axles having suspensions above the axles mounted to a frame inboard of the wheel assemblies. After allowing for suspension deflection and tire clearance, the load carrying deck for these structures is typically unnecessarily high off of the ground. Accordingly, self-lifting attachments have to allow for suspension deflection when loading such a truck. This normally requires expensive hydraulically actuated mechanisms.
Due to the fact that the suspension is mounted inboard of the wheel assemblies, the load center of gravity is unnecessarily high and the loaded vehicles are subject to excessive sway or to limited side angle use. Rigid, non-articulated trucks are generally a high investment item which results in the use of a dedicated vehicle, for example a tanker vehicle, a flat bed vehicle or a dump body vehicle. Dedicated vehicles lack the ability to be versatile for varying loads.
Because prior art trailers for trucks or the like are higher than necessary, much load-carrying capability is lost between the lower part of the trailer and the road. Furthermore, state of the art trucks generally do not have efficient capability to pick up their load from the ground level. Instead, they require other equipment such as fork lifts, cranes or a loading dock to load and/or unload the cargo. Such trucks lose much efficiency when they cannot unload their cargo precisely where it is needed to be delivered without the use of such aforementioned specialized loading and unloading equipment.